Chapter 7 Quiz
Complete the following statements regarding the steps necessary to copy a DNA sequence during PCR: 1) The two original strands of the DNA molecule can be separated by _____.
1) heat, 2) DNA polymerase; complementary nucleotides
If the DNA of a single chromosome was stretched out it would be how many meters long?
1-3 meters
How many STRs are typically used to create a profile in forensic investigations?
15
We inherit ____ chromosome of each pair from our mother and the other from our father for a total of ____ chromosomes.
1; 46
Every person has ___ copies of STR's?
2
How many hydrogen bonds do A's and T's have between them?
2
Human cells have how many chromosomes?
23
The ______ chromosomes in a typical human cell are found in the ________.
23; nucleus
How many hydrogen bonds do G's and C's have between them?
3
The _____ chromosomes in a human cell from inside the cheek are found in the _____.
46; nucleus
If you start with one copy of a DNA fragment, how many rounds of PCR will it take to end up with a total of 32 copies?
5
You are investigating a crime. The DNA profile database has no perfect matches to the DNA collected at the crime scene. However, one profile in the database has at least one band in common with the crime scene DNA at every STR site. Which statement is the most likely conclusion can you draw?
A parent-child relationship exists between the DNA collected at the crime scene and the DNA in the database.
You can detect DNA that is specifically from the X chromosome in a DNA sample from a person. Why can't you definitively determine the sex of that person (male or female) from the presence of the X chromosome?
Both males and females have an X chromosome and you would have to check for the presence of a Y chromosome.
Each chromosome contains _____.
DNA and proteins
Each chromosome contains?
DNA and proteins
Which of the following statements about PCR is true?
DNA polymerase is the enzyme that copies DNA in PCR.
Which statement about PCR is true?
DNA polymerase is the enzyme that copies DNA in PCR.
What naturally occurring process does PCR mimic in a test tube?
DNA replication
Which STR will have migrated farthest through an electrophoresis gel?
GAAG repeated twice
Which STR will have migrated farthest through an electrophoresis gel?
GAAG repeated twice?
Human red blood cells are enucleated (i.e., they do not have nuclei). Is it possible to isolate DNA from red blood cells? Why or why not?
No, the genomic DNA is found only in nucleated cells.
What is the purpose of careful primer design before PCR?
Primers indicate the section of DNA that will be amplified and mark where DNA polymerase begins replication
If the sequence of one strand of DNA is AGTCTAGC, what is the sequence of the complementary strand?
TCAGATCG
From the STRs used in a forensic investigation, which STRs on which chromosomes would be particularly useful in determining whether crime scene evidence was left by a female or a male?
Y chromosome STR
What is a chromosome and where is it found?
a single, large DNA molecule wound around proteins.
Each nucleotide consists of?
a sugar, phosphate group, and a base
What are the 4 different type of nucleotide bases?
adenine (A), thymine (T), guanine (G), and cytosine (C).
What happens in the 1st step of replication?
an enzyme called helicase unwinds the helix, and the 2 strands "unzip" from each other.
The 2 strands forming a double helix are considered to be what
complementary
You are studying the DNA profile of an individual, and you are looking at the results for a chromosome with just one STR site. How many bands will you see?
either 1 or 2
DNA evidence can give an investigator information regarding which of the following?
family relationships between suspects and the identity of an individual based on a profile
Children who inherit 2 x's from each parent are what
females
The entire sequence of DNA in a cell used for DNA profiling is called the _____.
genome
What type of bond holds the DNA double helix together?
hydrogen bond
Polymerase Chain Reaction (PCR) takes place where?
in a test tube
DNA is found where?
in the nucleus
Children who inherit a y from dad and an x from mom are what?
males
Is hair analysis reliable?
not always
Each subunit of DNA is called a ________.
nucleotide
An individual's STR may vary from the same STR of another individual by the _____.
number of times a particular sequence is repeated.
Genome is generally what?
one complete strand of genetic instructions encoded in the DNA of an organism.
DNA replication is said to be semiconservative because a newly replicated, double-stranded DNA molecule consists of?
one old strand and one new strand
DNA replication is said to be semiconservative because a newly replicated, double-stranded DNA molecules consists of _____.
one old strand and one new strand
In addition to the base, what are the other components of a nucleotide?
phosphate and sugar
In addition to the base, what are the other components of a nucleotide?
phosphate group and sugars
How does PCR work?
scientists add nucleotides to a small sample of DNA, the DNA polymerase enzyme , and primers (short segments of DNA). The DNA is first heated to separate strands, and then cooled to allow the primers to associate with the DNA and new nucleotides to be added by DNA polymerase.
DNA replication is considered to be what?
semi-conservative, just meaning that each newly made DNA molecule has one original DNA strand and one new DNA strand.
Gel electrophoresis separates DNA for profiling based on the _____.
size (length)
DNA testing became a _______ part of court cases.
standard
A DNA molecule is made up of two strands of _____ linked together in long chains.
subunits
Which chromosome determines a person's sex?
the 23rd
What varies among person to person in STR's?
the exact length of str's
Which phrase represents genetic variation between individuals?
the number of STRs in their genomes
An individual's STR may vary from the same STR of another individual by?
the number of times the sequence is repeated
Which of the following represents genetic variation between the individuals?
the sequence of nucleotides along the length of each chromosome.
What forms the "backbone" of the helix?
the sugars and phosphates
What happens after the 2 strands "unzip" from each other during replication?
then the enzyme DNA polymerase builds a new strand of DNA along each unzipped strand Then free nucleotides floating inside the cell's nucleus are added to each new strand in a sequence that is complimentary to the nucleotide sequence on the original template strand. The end result is 2 complete double-stranded molecules of DNA.
Which of the following is NOT a nucleotide found in DNA?
uracil (U)
Which of these is NOT a nucleotide found in DNA?
uracil (U)
Men have an __ and a ___, and pass on one or the other and women have ___ x's ad therefore can only pass on an x.
x & y; 2
Which person would have DNA that is least similar to yours?
your mother's brother
